Snowmobile heat exchanger assembly

ABSTRACT

A heat exchanger assembly has a top par and a bottom part joined to the top part. At least one of the top and bottom parts defines a recess. The top and bottom parts define therebetween a passage formed in part by the recess. The passage has a first portion of the passage extending along a first side of the heat exchanger assembly; a second portion of the passage extending along a second side of the heat exchanger assembly; an inlet fluidly communicating with the first portion of the passage near a first end of the passage; and an outlet fluidly communicating with the second portion of the passage near a second end of the passage. Fluid enters the passage via the inlet, then flows in the first portion of the passage, then flows in the second portion of the passage, and then exits the passage via the outlet.

CROSS-REFERENCE

The present application is a continuation of U.S. patent applicationSer. No. 15/439,210, filed Feb. 22, 2017, which is acontinuation-in-part of International Patent Application No.PCT/IB2014/064343, filed Sep. 9, 2014. Through International PatentApplication No. PCT/IB2014/064343, the present application is acontinuation of U.S. patent application Ser. No. 14/473,036, filed Aug.29, 2014, which claims priority to U.S. Provisional Patent ApplicationNo. 61/872,204, filed Aug. 30, 2013. The entirety of these fourapplications is incorporated herein by reference.

FIELD OF TECHNOLOGY

The present technology relates to heat exchanger assembly forsnowmobiles.

BACKGROUND

Snowmobiles are powered by engines that need to be cooled. In somesnowmobiles, a coolant is circulated around and through the enginethereby absorbing the heat generated by the engine. When the hot coolantleaves the engine, it needs to be cooled before being returned to theengine. To do so, the coolant is circulated through one or more heatexchanger assemblies.

FIG. 1 illustrates an exemplary implementation of a prior artarrangement of heat exchanger assemblies for a snowmobile. Thearrangement includes a front heat exchanger assembly 1000 and a heatexchanger assembly 1002.

The front heat exchanger assembly 1000 has a body 1004 defining aninternal volume, an outlet pipe 1006 and an inlet pipe 1008. The pipes1006, 1008 are welded to the body 1004. Fins 1010 are formed on the backof the body 1004. The front heat exchanger 1000 defines in part a frontof a tunnel of the snowmobile.

The heat exchanger assembly 1002 defines in part a top of the tunnel ofthe snowmobile. The heat exchanger assembly 1002 has a body 1012, andinlet pipe 1014, an outlet pipe 1016, and a connector 1018. Fins 1020are formed on the bottom of the body 1012. The body 1012 is formed bybeing extruded. The extrusion process forms two passages 1022, 1024. Theconnector 1018, also formed by extrusion, is connected to the back ofthe two passages 1022, 1024 to fluidly connect the two together therebyforming a single passage. The passages 1022, 1024 are capped at theirfront ends. The inlet pipe 1014 is welded at a front of the passage 1022and the outlet pipe 1016 is welded at a front of the passage 1024.

A pipe (not shown) connects the inlet pipe 1014 of the heat exchangerassembly 1002 to the engine to receive hot coolant from the engine.Another pipe (not shown) connects the outlet pipe 1016 of the heatexchange assembly 1002 to the inlet pipe 1008 of the heat exchangerassembly 1000 to allow coolant to flow from the heat exchanger assembly1002 to the heat exchanger assembly 1000. Another pipe (not shown)connects the outlet pipe 1006 of the heat exchanger assembly 1000 to theengine to return cooled coolant to the engine.

During operation of the snowmobile, coolant flows from the engine to theheat exchanger assembly 1002. In the heat exchanger assembly 1002,coolant first flows through the passage 1022, then through the connector1018, and then through the passage 1024. From the passage 1024 thecoolant flows to the heat exchanger assembly 1000. From the heatexchanger assembly 1000, the coolant is returned to the engine.

The coolant in the heat exchanger assemblies 1000, 1002 is cooled by acombination of air flowing along the surfaces of the heat exchangerassemblies 1000, 1002 and snow being projected on the surfaces of theheat exchanger assemblies 1000, 1002 by the drive track of thesnowmobile.

Although the arrangement of the heat exchanger assemblies 1000, 1002effectively cools the coolant of the engine, it has some disadvantages.

First, the heat exchanger assemblies 1000, 1002 are separate from eachother, which increases the complexity of their assembly to thesnowmobile.

Also, since the body 1012 of the heat exchanger assembly 1002 isextruded, the passages 1022, 1024 need to have a constantcross-sectional area along their lengths. As such, they are not shapedto take mostly advantage of the regions where more cooling can occursuch as where the snow is being sprayed by the drive track. Therefore,the overall internal volume of the heat exchanger assembly 1002 isgreater than necessary, which results in a larger volume of coolantbeing provided in the cooling system. Therefore, the snowmobile isheavier than necessary due to the coolant.

Finally, also due to the manner in which the bodies 1004, 1012 of theheat exchanger assemblies 1000, 1002 are manufactured, the pipes 1006,1008, 1014 and 1016 are welded generally perpendicular to the surfaceson which they are welded. This is because placing the pipes 1006, 1008,1014 and 1016 at an angle to their respective connection surfaces wouldmake welding difficult. As a result, the pipes 1006, 1008, 1014 and 1016take more room by being perpendicular then if they were disposed atanother angle.

Accordingly, it would be desirable to have a heat exchanger assemblythat can replace two heat exchanger assemblies such as the onesdescribed above.

It would also be desirable to have a heat exchanger assembly that takesadvantage of areas where more cooling can occur.

It would also be desirable to have a heat exchanger assembly thatfacilitates the welding of at least one of the inlet and outlet pipes atan angle to the surface to which it is being welded.

SUMMARY

It is an object of the present technology to ameliorate at least some ofthe inconveniences present in the prior art.

According to one aspect of the present technology, there is provided aheat exchanger assembly having a front portion, a middle portionrearward of the front portion, a rear portion rearward of the middleportion, a top part and a bottom part disposed below the top part. Atleast one of the front and rear portions is curved from the middleportion. The at least one of the front and rear portions extends belowthe middle portion. The bottom part is joined to the top part. At leastone of the top and bottom parts defines a recess. The top and bottomparts define therebetween a passage formed in part by the recess. Awidth of the passage varies along a length of the heat exchangerassembly. The passage has an inlet and an outlet.

According to some implementations of the present technology, the frontportion is curved from the middle portion.

According to some implementations of the present technology, the rearportion is curved from the middle portion.

According to some implementations of the present technology, the bottompart defines the recess.

According to some implementations of the present technology, the toppart defines at least one other recess. The passage is also formed inpart by the at least one other recess.

According to some implementations of the present technology, the passageextends longitudinally along a first lateral side of the heat exchanger,then laterally along the rear portion, then longitudinally along asecond lateral side of the heat exchanger and then laterally along thefront portion.

According to some implementations of the present technology, the passageextends at least in part along the middle portion and the at least oneof the front and rear portions.

According to some implementations of the present technology, at least aportion of the passage defined in the middle portion is wider than atleast another portion of the passage defined in the middle portion.

According to some implementations of the present technology, at least aportion of the passage is thicker than at least another portion of thepassage.

According to some implementations of the present technology, the recessis a first recess and the passage is a first passage. The heat exchangerassembly also has another part defining a second recess. The other partis joined to one of the top and bottom parts. The other part and the oneof the top and bottom parts to which the other part is joined definetherebetween a second passage formed in part by the second recess. Thesecond passage has another inlet and another outlet. The second passageis fluidly separate from the first passage.

According to some implementations of the present technology, the otherpart is curved. The other part is joined to the middle portion and theat least one of the front and rear portions that is curved from themiddle portion.

According to some implementations of the present technology, the firstpassage extends at least in part longitudinally along one side of thesecond passage.

According to some implementations of the present technology, the passageextends at least in part along the front portion. A width of a portionof the passage extending along the front portion is at least threequarters of a width of the front portion.

According to some implementations of the present technology, the inletof the passage is rearward of the outlet of the passage. From theoutlet, the passage extends forwardly then laterally.

According to some implementations of the present technology, the recessextends at least in part along the middle portion and the front portionand is curved to follow a curvature defined by the front portion and themiddle portion.

According to another aspect of the present technology, there is provideda snowmobile having a frame having a tunnel, a motor supported by theframe, at least one ski connected to the frame, a rear suspensionassembly connected to the tunnel, and a drive track disposed around therear suspension assembly and at least in part below the tunnel. Thedrive track is operatively connected to the motor. At least a portion ofa top of the tunnel and at least a portion of a front of the tunnel areformed by a heat exchanger assembly adapted to have at least one motorfluid flowing therethrough for cooling the at least one motor fluid. Theheat exchanger assembly has a front portion, a middle portion rearwardof the front portion, a rear portion rearward of the middle portion, atop part and a bottom part disposed below the top part. The frontportion is curved from the middle portion to form the front portion ofthe tunnel. The front portion extends below the middle portion. Themiddle and rear portions form the top portion of the tunnel. The bottompart is joined to the top part. At least one of the top and bottom partsdefines a recess. The top and bottom parts define therebetween a passageformed in part by the recess. A width of the passage varies along alength of the heat exchanger assembly. The passage has an inlet and anoutlet.

According to some implementations of the present technology, the bottompart defines the recess.

According to some implementations of the present technology, the toppart defines at least one other recess. The passage is also formed inpart by the at least one other recess.

According to some implementations of the present technology, drivesprockets operatively connect the motor to the drive track. The passageextends at least in part along the middle portion and the front portion.A first portion of the passage disposed along the front portion forwardof an axis of rotation of the drive sprockets is wider than a secondportion of the passage disposed rearward of the axis of rotation of thedrive sprockets.

According to some implementations of the present technology, the rearsuspension assembly has rear idler wheels and middle idler wheelsdisposed forward and above the rear idler wheels. At least a portion ofthe passage defined in the middle portion is wider than at least anotherportion of the passage defined in the middle portion. The wider portionof the passage defined in the middle portion is disposed at least inpart forward of an axis of rotation of the middle idler wheels.

According to some implementations of the present technology, the recessis a first recess and the passage is a first passage adapted to have afirst motor fluid flowing therethrough. The heat exchanger assembly alsohas another part defining a second recess. The other part being joinedto one of the top and bottom parts. The other part and the one of thetop and bottom parts to which the other part is joined definetherebetween a second passage formed in part by the second recess. Thesecond passage has another inlet and another outlet. The second passageis fluidly separate from the first passage. The second passage isadapted to have a second motor fluid flowing therethrough.

According to some implementations of the present technology, the inletand outlet of the passage fluidly communicate with the motor.

According to one aspect of the present technology, there is provided amethod of manufacturing a heat exchanger comprising: curving a frontportion of a first part from a middle portion of the first part, thefirst part being made of sheet metal; curving a front portion of asecond part from a middle portion of the second part, a curvature of thesecond part corresponding to a curvature of the first part, the secondpart being made of sheet metal; stamping a recess in the second part, awidth of the recess varying along a length of the second part; formingfirst and second apertures in one of the first and second parts; andjoining the first part to the second part thereby forming a passagebetween the recess and the first part, the first aperture fluidlycommunicating with the passage to form an inlet of the passage, thesecond aperture fluidly communicating with the passage to form an outletof the passage.

According to some implementations of the present technology, the methodfurther comprises stamping a recess in the first part. The passage isalso formed between the second part and the recess in the first part.

According to some implementations of the present technology, joining thefirst part to the second part includes welding the second part to thefirst part.

According to some implementations of the present technology, welding thesecond part to the first part includes welding a periphery of the recessto the first part.

According to some implementations of the present technology, the firstand second apertures are formed in the first part.

According to some implementations of the present technology, the methodfurther comprises stamping a protrusion in the one of the first andsecond parts in which the first and second apertures are formed. Formingthe first and second apertures in the one of the first and second partsincludes forming one of the first and second apertures in theprotrusion.

According to some implementations of the present technology, the methodfurther comprises welding a pipe to the protrusion around the one of thefirst and second apertures.

According to some implementations of the present technology, an initialthickness of the sheet metal forming the first part is equal to aninitial thickness of the sheet metal forming the second part.

For purposes of this application, terms related to spatial orientationsuch as forwardly, rearward, upwardly, downwardly, left, and right, areas they would normally be understood by a driver of the vehicle sittingthereon in a normal riding position. Terms related to spatialorientation when describing or referring to components or sub-assembliesof the vehicle, separately from the vehicle, such as a heat exchangerassembly for example, should be understood as they would be understoodwhen these components or sub-assemblies are mounted to the vehicle,unless specified otherwise in this application.

Implementations of the present technology each have at least one of theabove-mentioned object and/or aspects, but do not necessarily have allof them. It should be understood that some aspects of the presenttechnology that have resulted from attempting to attain theabove-mentioned object may not satisfy this object and/or may satisfyother objects not specifically recited herein.

Additional and/or alternative features, aspects and advantages ofimplementations of the present technology will become apparent from thefollowing description, the accompanying drawings and the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present technology, as well as otheraspects and further features thereof, reference is made to the followingdescription which is to be used in conjunction with the accompanyingdrawings, where:

FIG. 1 is a perspective view taken from a top, front, left side of aprior art arrangement of heat exchanger assemblies;

FIG. 2 is a left side elevation view of a snowmobile;

FIG. 3 is a perspective view taken from a top, front, left side of aportion of the frame of the snowmobile of FIG. 2;

FIG. 4 is a perspective view taken from a bottom, rear, left side of afirst implementation of a heat exchanger assembly of the snowmobile ofFIG. 2;

FIG. 5 is a top plan view of the heat exchanger assembly of FIG. 4;

FIG. 6 is a bottom plan view of the heat exchanger assembly of FIG. 4;

FIG. 7 is a right side elevation view of the heat exchanger assembly ofFIG. 4;

FIG. 8 is a rear elevation view of the heat exchanger assembly of FIG.4;

FIG. 9 is a front elevation view of the heat exchanger assembly of FIG.4;

FIG. 10 is an exploded view of the heat exchanger assembly of FIG. 4;

FIG. 11 is a perspective view taken from a bottom, rear, left side of asecond implementation of a heat exchanger assembly of the snowmobile ofFIG. 2;

FIG. 12 is a bottom plan view of the heat exchanger assembly of FIG. 11;

FIG. 13 is a cross-sectional view of the heat exchanger assembly of FIG.11 taken through line 13-13 of FIG. 12;

FIG. 14 is a cross-sectional view of the heat exchanger assembly of FIG.11 taken through line 14-14 of FIG. 12;

FIG. 15 is a cross-sectional view of the heat exchanger assembly of FIG.11 taken through line 15-15 of FIG. 12;

FIG. 16 is a cross-sectional view of the heat exchanger assembly of FIG.11 taken through line 16-16 of FIG. 12;

FIG. 17 is a left side elevation view of a drive sprocket, analternative implementation of a suspension assembly and a portion of adrive track of the snowmobile of FIG. 2 and the heat exchanger assemblyof FIG. 11;

FIG. 18 is a perspective view taken from a bottom, rear, left side ofthe components of FIG. 17;

FIG. 19 is a perspective view taken from a bottom, rear, left side ofthe components of FIG. 17 with the track portion removed and thesuspension assembly in a compressed configuration;

FIG. 20 is a perspective view taken from a bottom, rear, left side of abottom part of a third implementation of a heat exchanger assembly ofthe snowmobile of FIG. 2;

FIG. 21 is a perspective view taken from a bottom, rear, left side of abottom part of a fourth implementation of a heat exchanger assembly ofthe snowmobile of FIG. 2;

FIG. 22 is a right side elevation view of the bottom part of the heatexchanger assembly of FIG. 21;

FIG. 23 is a bottom plan view of the bottom part of the heat exchangerassembly of FIG. 21;

FIG. 24 is a rear elevation view of the bottom part of the heatexchanger assembly of FIG. 21;

FIG. 25 is a perspective view taken from a bottom, rear, left side of abottom part of a fifth implementation of a heat exchanger assembly ofthe snowmobile of FIG. 2;

FIG. 26 is a perspective view taken from a bottom, rear, left side of asixth implementation of a heat exchanger assembly of the snowmobile ofFIG. 2;

FIG. 27 is a perspective view taken from a top, front, left side of theheat exchanger assembly of FIG. 26;

FIG. 28 is top plan view of the heat exchanger assembly of FIG. 26;

FIG. 29 is a cross-sectional view of the heat exchanger assembly of FIG.26 taken through line 29-29 of FIG. 28;

FIG. 30 is a cross-sectional view of the heat exchanger assembly of FIG.26 taken through line 30-30 of FIG. 28;

FIG. 31 is a cross-sectional view of a portion of the heat exchangerassembly of FIG. 26 taken through line 31-31 of FIG. 28;

FIG. 32 is a perspective view taken from a bottom, rear, left side of aseventh implementation of a heat exchanger assembly of the snowmobile ofFIG. 2;

FIG. 33 is a top plan view of the heat exchanger assembly of FIG. 32;

FIG. 34 is a perspective view taken from a bottom, rear, left side of aeighth implementation of a heat exchanger assembly of the snowmobile ofFIG. 2;

FIG. 35 is a top plan view of the heat exchanger assembly of FIG. 34;

FIG. 36 is a top plan view of a tunnel of the snowmobile of FIG. 2having an ninth implementation of a heat exchanger assembly;

FIG. 37 is a top plan view of the tunnel of the snowmobile of FIG. 2 andthe ninth implementation of the heat exchanger assembly with a top partof the heat exchanger assembly removed;

FIG. 38 is a perspective view taken from a bottom, rear, left side of atenth implementation of a heat exchanger assembly of the snowmobile ofFIG. 2;

FIG. 39 is a bottom plan view of the heat exchanger assembly of FIG. 38;

FIG. 40 is a rear elevation view of the heat exchanger assembly of FIG.38;

FIG. 41 is a cross-sectional view of the heat exchanger assembly of FIG.38 taken through line 41-41 of FIG. 40;

FIG. 42 is a cross-sectional view of the heat exchanger assembly of FIG.38 taken through line 42-42 of FIG. 39 with a drive sprocket of thesnowmobile of FIG. 2;

FIG. 43 is a left side elevation view of the suspension assembly of FIG.17 in a compressed configuration, the drive sprocket and the drive trackof the snowmobile of FIG. 2, and the heat exchanger assembly of FIG. 38;

FIG. 44 is a cross-sectional view of the components of FIG. 43 takenthrough line 44-44 of FIG. 43;

FIG. 45 is a slice of the components of FIG. 43 taken through line 44-44of FIG. 43; and

FIG. 46 is a rear elevation view of an eleventh implementation of a heatexchanger assembly of the snowmobile of FIG. 2.

DETAILED DESCRIPTION

Referring to FIG. 2, a snowmobile 10 includes a forward end 12 and arearward end 14. The snowmobile 10 includes a vehicle body in the formof a frame or chassis 16 which, as can be seen in FIGS. 2 and 3,includes a tunnel 18, an engine cradle portion 20, a front suspensionmodule 22 and an upper structure 24.

A motor 26 (schematically illustrated in FIG. 2), which in theillustrated implementation is an internal combustion engine, is carriedin an engine compartment defined in part by the engine cradle portion 20of the frame 16. A fuel tank 28, supported above the tunnel 18, suppliesfuel to the engine 26 for its operation. Coolant used to cool the engine26 is circulated through a heat exchanger assembly 100 (FIG. 3),described in greater detail below, to be cooled. The heat exchangerassembly 100 forms part of the tunnel 18.

An endless drive track 30 is disposed generally under the tunnel 18. Thedrive track 30 is operatively connected to the engine 26 through a belttransmission system (not shown) and a reduction drive (not shown). Theendless drive track 30 is driven to run about a rear suspension assembly32 connected to the frame 16 for propulsion of the snowmobile 10. Theendless drive track 30 has a plurality of lugs 31 extending from anouter surface thereof to provide traction to the track 30.

The rear suspension assembly 32 includes drive sprockets 34, idlerwheels 36 and a pair of slide rails 38 in sliding contact with theendless drive track 30. The drive sprockets 34 are mounted on a driveaxle 35 and define a sprocket axis 37. The slide rails 38 are attachedto the tunnel 18 by front and rear suspension arms 40 and shockabsorbers 42. It is contemplated that the snowmobile 10 could beprovided with a different implementation of a rear suspension assembly32 than the one shown herein.

A straddle-type seat 60 is positioned atop the fuel tank 28. A fuel tankfiller opening covered by a cap 92 is disposed on the upper surface ofthe fuel tank 28 in front of the seat 60. It is contemplated that thefuel tank filler opening could be disposed elsewhere on the fuel tank28. The seat 60 is adapted to accommodate a driver of the snowmobile 10.The seat 60 could also be configured to accommodate a passenger. Afootrest 64 is positioned on each side of the snowmobile 10 below theseat 60 to accommodate the driver's feet.

At the front end 12 of the snowmobile 10, fairings 66 enclose the engine26 and the belt transmission system, thereby providing an external shellthat not only protects the engine 26 and the transmission system, butcan also make the snowmobile 10 more aesthetically pleasing. Thefairings 66 include a hood 68 and one or more side panels which can beopened to allow access to the engine 26 and the belt transmission systemwhen this is required, for example, for inspection or maintenance of theengine 26 and/or the transmission system. A windshield 69 connected tothe fairings 66 acts as a wind screen to lessen the force of the air onthe rider while the snowmobile 10 is moving.

Two skis 70 positioned at the forward end 12 of the snowmobile 10 areattached to the front suspension module 22 of the frame 16 through afront suspension assembly 72. The front suspension module 22 isconnected to the front end of the engine cradle portion 20. The frontsuspension assembly 72 includes ski legs 74, supporting arms 76 and balljoints (not shown) for operatively connecting to the respective ski leg74, supporting arms 76 and a steering column 82.

A steering assembly 80, including the steering column 82 and a handlebar84, is provided generally forward of the seat 60. The steering column 82is rotatably connected to the frame 16. The lower end of the steeringcolumn 82 is connected to the ski legs 74 via steering rods (not shown).The handlebar 84 is attached to the upper end of the steering column 82.The handlebar 84 is positioned in front of the seat 60. The handlebar 84is used to rotate the steering column 82, and thereby the skis 70, inorder to steer the snowmobile 10. A throttle operator (not shown) in theform of a finger-actuated throttle lever is mounted to the right side ofthe handlebar 84. Other types of throttle operators, such as athumb-actuated throttle lever and a twist grip, are also contemplated. Abrake actuator (not indicated), in the form of a hand brake lever, isprovided on the left side of the handlebar 84 for braking the snowmobile10 in a known manner. It is contemplated that the windshield 69 could beconnected directly to the handlebar 84.

At the rear end of the snowmobile 10, a snow flap 94 extends downwardfrom the rear end of the tunnel 18. The snow flap 94 protects againstdirt and snow that can be projected upward from the drive track 30 whenthe snowmobile 10 is being driven. It is contemplated that the snow flap94 could be omitted.

The snowmobile 10 includes other components such as a display cluster,an exhaust system, an air intake system, and the like. As it is believedthat these components would be readily recognized by one of ordinaryskill in the art, further explanation and description of thesecomponents will not be provided herein.

Turning now to FIG. 3, the tunnel 18 will be described in more detail.The tunnel 18 has two side portions 96. Each side portion 96 is madefrom a bent piece of sheet metal. Each side portion has a horizontallyextending top portion 97 (FIG. 36) and is bent at its bottom to form arear part of the footrest 64. The heat exchanger assembly 100 rests onthe top portions 97 between the side portions 96, thereby forming amajority of the top and front of the tunnel 18. The heat exchangerassembly 100 is fastened, welded or otherwise connected to the sideportions 96. Trims 98 are disposed near the top of each side portion 96to hide the connection between the heat exchanger assembly 100 and theside portions 96 of the tunnel 18.

Turning now to FIGS. 4 to 10, the heat exchanger assembly 100 will bedescribed in more detail. The heat exchanger assembly 100 has a frontportion 102, a rear portion 104 and a middle portion 106 between thefront and rear portions 102, 104. As can be seen, the front portion 102is curved down from the middle portion 106 such that the front portion102 extends below the middle portion 106. As best seen in FIG. 10, theheat exchanger assembly 100 is made of two main parts: a top part 108and a bottom part 110.

The top part 108 is made of a piece of sheet metal that is curved downat its front. The front portion of the top part 108 is flat, and thencurves to the middle portion of the top part 108. The middle and rearportion of the top part 108 are flat. A plurality of apertures 112 (onlysome of which are labeled for clarity) are formed in the top part 108 topermit the attachments of various components of the snowmobile 10 to theheat exchanger assembly 100 such as the fuel tank 28. As can be seen inFIG. 10, an aperture is formed in the curved portion of the top part 108to form an outlet 114 of a passage (discussed below) of the heatexchanger assembly 100. As can be also seen in FIG. 10, another apertureis formed in the middle portion of the top part 108 rearward of theoutlet 114 to form an inlet 116 of the passage of the heat exchangerassembly 100. It is contemplated that the outlet 114 could be disposedrearward of the inlet 116 or that they could be at a same distance fromthe front of the top part 108. Although shown on the right side near afront of the top part 108, it is contemplated that the outlet 114 andinlet 116 could be anywhere on the top part 108 as long as the geometryof the passage discussed below is modified accordingly. An outlet pipe118 is welded or otherwise joined to the top part 108 around the outlet114 and an inlet pipe 120 is welded or otherwise joined to the top part108 around the inlet 116.

The bottom part 110 is made of a piece of sheet metal that is curveddown at its front such that its curvature matches the curvature of thetop part 108. Once curved, the bottom part 110 is stamped to form arecess 122. The piece of sheet metal from which the bottom part 110 ismade is initially shaped such that only a border 124 is left around therecess 122, thereby reducing the weight of the bottom part 110.Alternatively, it is contemplated that the sheet metal could be cutafter the recess 122 has been formed so as to only leave the border 124around the recess 122. It is also contemplated that the sheet metalcould not be cut. The border 124 of the bottom part 110 is welded orotherwise joined to the top part 108 to form the heat exchanger assembly100. Additional details regarding the method of manufacturing the heatexchanger assembly 100 will be provided further below.

By joining the top part 108 to the bottom part 110, a passage is formedbetween the recess 122 and the top part 108. The recess 122 defines theshape of the passage. This passage permits the flow of engine coolantthrough the heat exchanger assembly 100. Although in the presentimplementation the heat exchanger 100 is used to cool engine coolant, itis contemplated that it could be used to cool other motor fluids suchas, for example, oil used to lubricate the engine 26 or air to besupplied to the engine 26.

During operation of the engine 26, the hot engine coolant flows from theengine 26 through a pipe (not shown) connected to the inlet pipe 120,then through the inlet pipe 120 and then into the passage formed betweenthe top and bottom parts 108, 110 via the inlet 116.

As can be seen in FIG. 6, the inlet 116 (shown in dotted lines) isdisposed over a front of a narrow portion 134 of the passage. From theinlet 116, the coolant flows rearward into the narrow and long portion134 of the passage defined by a narrow part of the recess 122 andextending along the middle portion 106 on a right side thereof.

From the portion 134 of the passage, the coolant flows rearward andlaterally into a portion 132 of the passage defined by a wide part ofthe recess 122 along the rear portion 104 of the heat exchanger assembly100. In an exemplary implementation, a width of the passage in theportion 132 is at least three quarters of the width of the top part 108in the rear portion 104. The portion 132 of the passage is located abovethe rear idler wheels 36A (see FIG. 17). As the track 30 passes aroundthe rear idler wheels 36A, it projects snow onto the portion of thebottom part 110 defining the portion 132 of the passage. Making theportion 132 wide and long increases the amount of cooling obtained fromthis projected snow since a large surface is exposed to the projectedsnow.

From the portion 132 of the passage, the coolant flows forward into anarrow and long portion 130 of the passage defined by a narrow part ofthe recess 122 and extending along the middle portion 106 on a left sidethereof.

From the portion 130, the coolant flows forwardly and then laterallyinto a portion 128 of the passage defined by a wide part of the recess122 along the front portion 102 of the heat exchanger assembly 100. Ascan be seen, the portion 128 of the passage is curved to follow acurvature of the top part 108. In an exemplary implementation, a widthof the passage in the portion 128 is at least three quarters of thewidth of the top part 108 in the front portion 102. The portion 128 ofthe passage is located forwardly of the sprocket axis 37 (i.e. the axisof rotation of the sprockets 35). As the track 30 passes around thesprockets 35, it projects snow onto the portion of the bottom part 110defining the portion 128 of the passage. Making the portion 128 wide andlong increases the amount of cooling obtained from this projected snowsince a large surface is exposed to the projected snow.

From the portion 128 of the passage, the coolant flows rearward into anarrow portion 126 of the passage above which the outlet 114 is located(shown in dotted lines in FIG. 6). The coolant then flows out of thepassage via the outlet 114, through the outlet pipe 118 and finallythrough a pipe (not shown) connected between the outlet pipe 118 and theengine 26 to return the now cooled coolant to the engine 26.

Turning now to FIGS. 11 to 37, various alternative implementations ofthe heat exchanger assembly 100 will be described. For simplicity, theelements of each of the heat exchanger assemblies described below whichare similar to those of the heat exchanger assembly 100 or to elementsof another one of the heat exchanger assemblies described below havebeen labelled with the same reference numerals and will not be describedagain in detail.

Turning now to FIGS. 11 to 19, a heat exchanger assembly 200 will bedescribed. The heat exchanger assembly 200 has a top part 208 and abottom part 210. The bottom part 210 defines a recess 222. A passage isformed between the recess 222 and the top part 208. In the heatexchanger assembly 200, the portions 126 and 128 of the passage of theheat exchanger assembly 100 have been replaced by a single portion 228.The portion 228 is similar in shape to the portion 128 described aboveexcept that, as best seen in FIG. 17, the bottom part of the portion 228has a thickness T1 that is greater than a thickness T2 of the rest ofthe passage.

In the heat exchanger assembly 200, the portion 134 of the passage ofthe heat exchanger assembly 100 has been replaced by two long and narrowportions 234A, 234B and a wide portion 235 between the portions 234A,234B. As can be seen by comparing FIGS. 13 to 16, the portion 235 iswider than the portions 234A and 234B, but narrower than the portion132. Coolant flows from the inlet 116 (shown in dotted lines in FIG. 12)to the portion 234B, to the portion 235, then to the portion 234A andthen to the portion 132.

In the heat exchanger assembly 200, the portion 130 of the passage ofthe heat exchanger assembly 100 has been replaced by two long and narrowportions 230A, 230B and a wide portion 231 between the portions 230A,230B. As can be seen by comparing FIGS. 13 to 16, the portion 231 iswider than the portions 230A and 230B, but narrower than the portion132. Coolant flows from the portion 132 to the portion 230B, to theportion 231, then to the portion 230A and then to the portion 228.

FIGS. 17 to 19 show the heat exchanger assembly 200 in relation to arear suspension assembly 32′. The rear suspension assembly 32′ has maincomponents that are similar to those of the rear suspension assembly 32described above, but they are connected to each other differently. Asthe differences between the rear suspension assemblies 32 and 32′ arenot essential to the understanding of the operation of the heatexchanger assembly 200 they will not be described herein. The rearsuspension assembly 32′ has middle idler wheels 36B that are disposedforward and above the rear idler wheels 36A. The middle idler wheels 36Brotate about an axis of rotation 39.

The wider portions 231 and 235 of the passage of the heat exchangerassembly 200 are disposed along the middle portion 106 forward of theaxis of rotation 39 of the middle idler wheels 36B such that as thetrack 30 passes around the middle idler wheels 36B, it projects snowonto the portions of the bottom part 210 defining the portions 231 and235 of the passage. Making the portions 231 and 235 wide increases theamount of cooling obtained from this projected snow since a largesurface is exposed to the projected snow. In the present implementation,the portions 231 and 235 are disposed so as to extend both forward andrearward of a point P where a line 240 intersects the heat exchangerassembly 200 for all or most degrees of compression of the rearsuspension assembly 32′ in order help ensure that snow is projected onat least part of the portions 231 and 235 for all or most degrees ofcompression of the rear suspension assembly 32′. The line 240 is a linethat passes through the tops of lugs 31 disposed in a common row along aportion of the track 30 extending between the rear and middle idlerwheels 36A, 36B. As can be seen in FIGS. 18 and 19, the portions 231 and235 extend forward and rearward of the point P when the rear suspensionassembly 32′ is fully extended (FIG. 18) and when the rear suspensionassembly 32′ is fully compressed (FIG. 19).

The top portion 208 of the heat exchanger assembly 200 is similar to thetop portion 108 described above except that the outlet 114 has beenmoved forward in order to be aligned with the portion 228 of thepassage.

Turning now to FIG. 20, the bottom part 310 of another implementation ofa heat exchanger assembly will be described. It should be understoodthat although not shown, this other implementation of the heat exchangerassembly has a top part similar to the top parts described above, butshaped to match the lateral profile of the bottom part 310, and also hasinlet and outlet pipes. The bottom part 310 defines a recess 322. Apassage is formed between the recess 322 and the top part. The bottomportion 310 is similar to the bottom portion 210 described above exceptthat the portion 228 of the passage of the heat exchanger assembly hasbeen replaced by a portion 328 and the portion 132 has been replaced bya portion 332. The portion 328 is similar in shape to the portion 228described above except that it has a uniform thickness. The portion 332is similar in shape to the portion 132 except that it has a portion bentdown (i.e. sharply curved down). Also, instead of being curved down asin the above implementations, the front portion 102 is bent down (i.e.sharply curved down) in two places.

Turning now to FIGS. 21 to 24, the bottom part 410 of anotherimplementation of a heat exchanger assembly will be described. It shouldbe understood that although not shown, this other implementation of theheat exchanger assembly has a top part similar to the top partsdescribed above, but shaped to match the lateral profile of the bottompart 410, and also has inlet and outlet pipes. The bottom part 410defines a recess 422. A passage is formed between the recess 422 and thetop part. The bottom portion 410 is similar to the bottom portion 310described above except that the portions 230A, 230B of the passage havebeen replaced by a portion 430 from which the portion 231 extendslaterally and the portions 234A, 234B of the passage have been replacedby a portion 434 from which the portion 231 extends laterally. Theportions 430, 434 of the passage are thicker than the portions 230A,230B, 234A and 234B that they replace. The portions 430, 434 also have athickness T3 (FIG. 22) that is greater than the thicknesses T4, T5, T6,T7 (FIGS. 22 and 24) of the portions 328, 132, 231 and 235 respectively.

Turning now to FIG. 25, the bottom part 510 of another implementation ofa heat exchanger assembly will be described. It should be understoodthat although not shown, this other implementation of the heat exchangerassembly has a top part similar to the top parts described above, butshaped to match the lateral profile of the bottom part 510, and also hasinlet and outlet pipes. The bottom part 510 defines a recess 522. Apassage is formed between the recess 522 and the top part. The bottomportion 510 is similar to the bottom portion 210 described above exceptthat the portions 228, 231 and 235 of the passage have been replaced byportions 328, 531 and 535 respectively. The portions 531 and 535 arelonger and disposed more forward along the middle portion 106 than theportions 231 and 235 of the heat exchanger assembly 200 in order toaccommodate a different geometry of rear suspension assembly.

Turning now to FIGS. 26 to 31, a heat exchanger assembly 600 will bedescribed. The heat exchanger assembly 600 has a top part 608 joined toa bottom part 610 to form a passage therebetween. The top part 608 issimilar in shape to the top part 210 but is stamped to form two long andnarrow recesses 636, 638. As best seen in FIG. 31, a protrusion 640having a generally triangular cross-section is also stamped in the toppart 608. The aperture forming the inlet 116 is formed in the frontangled side of the protrusion 640. It is contemplated that theprotrusion 640 could have other shapes. For example, it is contemplatedthat the protrusion 640 could be generally hemispheric, thus permittingthe inlet 116 to be formed in almost any desired orientation. The inletpipe 120 is welded to this surface around the inlet 116. As a result,the inlet pipe 120 is disposed at an angle to the middle portion 106,but since the inlet pipe 120 is perpendicular to the front surface ofthe protrusion 640, welding the inlet pipe 120 to the top part 608 ismore easily accomplished than if there were no protrusion 640. It iscontemplated that protrusions similar to the protrusion 640 could beprovided for welding the outlet and inlet pipes 118, 120 of the variousimplementations of heat exchanger assemblies described herein.

The bottom part 610 is curved at its front to match the curvature of thetop part 608. The bottom part 610 is stamped to form three recesses622A, 622B and 622C. The recess 622A and the top part 608 form a frontpassage portion 328 and a long and narrow passage portion 630A. Therecess 622B and the top part 608 form a long and narrow passage portion630B, a rear passage portion 132 and a long and narrow passage portion634A. The recess 622C and the top part 608 form a long and narrowpassage portion 634B.

The recess 638 in the top part 608 and the flat portion 631 of thebottom part 610 between the passage portions 630A and 630B form apassage portion 639. As best seen in FIG. 29, the passage portion 639communicates with the passage portion 630A at its front and with thepassage portion 630B at its rear. The recess 636 in the top part 608 andthe flat portion 635 of the bottom part 610 between the passage portions634A and 634B form a passage portion 637. As best seen in FIG. 30, thepassage portion 637 communicates with the passage portion 634B at itsfront and with the passage portion 634A at its rear.

During operation of the engine 26, coolant enters the heat exchangerassembly 600 via the inlet pipe 120 and the inlet 116. The coolant thenflows consecutively through the passage portions 634B, 637, 634A, 132,630B, 639, 630A and 328. From the portion 328 of the passage, thecoolant then flows through the outlet 114 and the outlet pipe 118 to bereturned to the engine 26.

Turning now to FIGS. 32 and 33, a heat exchanger assembly 700 will bedescribed. The heat exchanger assembly 700 has a top part 708 joined toa bottom part 710 to form a passage therebetween and another bottom part750 joined to the top part 708 to form another passage therebetween.

The bottom part 710 is stamped to form a recess 722 to define thepassage between the bottom part 710 and the top part 708. The passageformed by the bottom part 710 is similar to the passage formed in theheat exchanger assembly 100 except that the portions 126, 128 have beenreplaced by a portion 328.

The bottom part 750 is stamped to form a recess 752 with a border 754around it. The border 754 is used to weld or otherwise join the bottompart 750 to the bottom of the top part 708. As can be seen, the recess752 is generally L-shaped and extends in part along the front portion102 and in part along the middle portion 106. As a result, the recess752 is also curved to follow the curvature of the top part 708. Sincethe recess 752 and the top part 708 define a shape of the passage, thepassage formed by the recess 752 is generally L-shaped and, has seenfrom a lateral side of the heat exchanger assembly 700, is curved. Inthis this position, the passage formed by the bottom part 750 can becooled by snow projected by the drive track 30 during operation of thesnowmobile 10. The passage portion 328 extends laterally along a frontof the passage formed by the bottom part 750. The passage portion 130extends longitudinally along a left side of the passage formed by thebottom part 750. The rear portion of the passage formed by the bottompart 750 is disposed laterally between the passage portions 130 and 134.It is contemplated that instead of or in addition to the bottom part750, another passage could be formed by another part having a recessthat is joined to a top of the top part 708.

The top portion 708 is shape like the top portion 108 of the heatexchanger 100 but has two apertures formed therein to form the inlet 756and the outlet 758 (shown in dotted lines in FIG. 32) of the passageformed by the bottom part 750. As can be seen in FIG. 33, an inlet pipe760 is welded or otherwise joined to the top part 708 around the inlet756 and an outlet pipe 762 is welded or otherwise joined to the top part708 around the outlet 758.

The passage formed by the bottom part 750 is fluidly separate from thepassage formed by the bottom part 710. As such, the passage formed bythe bottom part 750 is used to cool a motor fluid other than the enginecoolant such as oil used to lubricate the engine 26 or air to besupplied to the engine 26 by having this other motor fluid flowingthrough this other passage.

Turning now to FIGS. 34 and 35, a heat exchanger assembly 800 will bedescribed. The heat exchanger assembly 800 has a top part 808 joined tothe bottom part 610 described above to form a first passage therebetweenand the bottom part 750 described above joined to the top part 808 toform a second passage therebetween. As such, the heat exchanger assembly800 can also be used to cool two different motor fluids. The top part808 is similar to the top part 608 described above, but has theapertures forming the inlet 756 and the outlet 758 of the secondpassage. The inlet and outlet pipes 760, 762 are welded or otherwisejoined to the top part 808 around the inlet 756 and outlet 758respectively.

Turning now to FIGS. 36 and 37, a heat exchanger assembly 900 will bedescribed. The heat exchanger assembly 900 has a top part 908 joined tothe bottom part 210 described above to form a first passage therebetweenand the bottom part 750 described above joined to the top part 908 toform a second passage therebetween. As such, the heat exchanger assembly900 can also be used to cool two different motor fluids. The top part908 is similar to the top part 208 described above, but has theapertures forming the inlet 756 and outlet 758 of the second passage.The inlet and outlet pipes 760, 762 are welded or otherwise joined tothe top part 908 around the inlet 756 and outlet 758 respectively.

Although the heat exchanger assemblies described above are designed totake advantage of the snow projected by the drive track 30 of thesnowmobile 10 during operation of the snowmobile 10, it should beunderstood that the air around the heat exchanger assemblies also coolsthe motor fluid(s) flowing through the heat exchanger assemblies. It iscontemplated that fins or other types of heat sinks could be attached toat least some of the surfaces of the heat exchanger assemblies formingthe passage(s) described above to further increase cooling of the motorfluid(s) flowing through the passage(s).

A method of manufacturing the heat exchanger assembly 100 will now bedescribed. A similar method is used to manufacture the other heatexchangers described above.

A first part of sheet metal, such as aluminum, is cut to a desired shapein order to make the top part 108. A front portion of the first part ofsheet metal is curved from a middle portion of the first part of sheetmetal using a press or other suitable machine to form the top part 108.The apertures 112, the outlet 114 and the inlet 116 are then cut ordrilled into the top part 108. The apertures 112, the outlet 114 and theinlet 116 could also be stamped out of the top part 108 using a press.The outlet pipe 118 and the inlet pipe 120 are then welded or otherwiseconnected to the top part 108 around the outlet 114 and the inlet 116respectively.

A second part of sheet metal, such as aluminum, is cut to a desiredshape in order to make the bottom part 110. In one implementation, thefirst and second parts of sheet metal have the same initial thickness. Afront portion of the second part of sheet metal is curved from a middleportion of the second part of sheet metal using a press or othersuitable machine such that a curvature of the second part of sheet metalcorresponds to a curvature of the top part 108. Then, using a press, therecess 122 is stamped in the second part of sheet metal thereby formingthe bottom part 110. This stamping also forms the border 124.

The top part 108 is then joined to the bottom part 110 thereby formingthe passage between the recess 122 and the top part 108. In the presentimplementation, the top part 108 is welded to the border 124 of thebottom part 110, such as by friction stir welding. However it iscontemplated that the top part 108 could be joined to the bottom part110 in other manners such as by brazing, bonding or fastening forexample. If fasteners are used, it is contemplated that a seal could bedisposed between the border 124 and the top part 110 to prevent themotor fluid to leak out of the passage.

It is contemplated that the top part 108 and the bottom part 110 couldbe made of other types of thin walled material. It is also contemplatedthat at least the bottom part 110 could be molded, in which case therecess 122 and border 124 would be formed in the mold.

To make a top part having recesses and protrusions such as the top part608, these are stamped in the sheet metal in a manner similar to whichthe recess 122 is formed in the bottom part 110. The part 750 is formedin a manner similar to the one used to make the bottom part 110 and isjoined to its corresponding top part in a similar manner.

Turning now to FIGS. 38 to 45, a heat exchanger assembly 1100 will bedescribed. The heat exchanger assembly 1100 has a top part 1108 and abottom part 1110. The bottom part 1110 defines a recess 1122. A passageis formed between the recess 1122 and the top part 1108. In the heatexchanger assembly 1100, the portion 228 of the passage of the heatexchanger assembly 200 has been replaced by a portion 1128. The portion1128 will be described in greater detail below.

In the heat exchanger assembly 1100, the portion 134 of the passage ofthe heat exchanger assembly 100 has been replaced by a short narrowportion 1134A, a long narrow portion 1134B and a wide portion 1135between the portions 1134A, 1134B. As best seen in FIG. 39, the portion1135 is wider than the portions 1134A and 1134B, but narrower than theportion 132. Coolant flows from the inlet 116 (shown in dotted lines inFIG. 39) to the portion 1134B, to the portion 1135, then to the portion1134A and then to the portion 132.

In the heat exchanger assembly 1100, the portion 130 of the passage ofthe heat exchanger assembly 100 has been replaced by a long narrowportion 1130A, a short narrow portion 230B and a wide portion 1131between the portions 1130A, 1130B. As best seen in FIG. 39, the portion1131 is wider than the portions 1130A and 1130B, but narrower than theportion 132. Coolant flows from the portion 132 to the portion 1130B, tothe portion 1131, then to the portion 1130A and then to the portion1128.

The wider portions 1131 and 1135 of the passage of the heat exchangerassembly 1100 are disposed in the rear half of the heat exchangerassembly 1100. Making the portions 1131 and 1135 wide increases theamount of cooling obtained from snow projected thereon since a largesurface is exposed to the projected snow.

With reference to FIGS. 40 to 42, the portion 1128 of the heat exchangerassembly 1100 will be described in more detail. The portion 1128 has acentral channel 1150 defined on an outer surface thereof. The centralchannel 1150 is laterally between two side sections 1152 and above abottom section 1154 of the portion 1128.

The side sections 1152 each have an arcuate part spanning an angle A1 ata radius R1 from the sprocket axis 37 (see FIG. 42) followed by astraight part up to the bottom section 1154 (as indicated by dottedlines 1155 in FIG. 40). The straight parts of the side sections 1152 areparallel to the top part 1108. The central channel 1150 defines anarcuate surface spanning an angle A2 at a radius R2 from the sprocketaxis 37 (see FIG. 42) up to the bottom section 1154. The angle A1 isless than the angle A2. The radius R2 is less than the radius R1. Assuch the thickness of the passage between the central channel 1150 andthe top part 1108 is less than the thickness of the passage between theside sections 1152 and the top part 1108. The main surface to the bottomsection 1154 is parallel to the top part 1108. The thickness of thepassage between the side sections 1152 and the top part 1108 is the sameas the thickness of the passage between the bottom section 1154 and thetop part 1108.

With reference to FIGS. 44 and 45, in the present implementation, thelugs 31 of the endless drive track 30 are provided with studs 1160 toimprove traction. It will be noted that the portions of the lugs 31 thatare laterally aligned with the portions 1130A and 1134B of the passageof the heat exchanger assembly 1100 are free of studs 1160. When therear suspension assembly 32′ is compressed as shown in FIGS. 43 to 45,and in other positions of the rear suspension assembly 32′ (not shown),the portions of the lugs 31 that are laterally aligned with the portions1130A and 1134B come into contact with the portions 1130A, 1134B, thuspreventing the studs 1160 located to the left and right of the portions1130A, 1134B from coming into contact with the bottom of the heatexchanger assembly 1100. It is contemplated that portions of the heatexchanger assemblies previously described above with respect to FIGS. 4to 37 could similarly prevent studs 1160 provided on the lugs 31 of theendless drive track 30 from coming into contact with a bottom surfacethereof.

As the central channel 1150 of the portion 1128 of the heat exchangerassembly 110 is disposed further from the drive sprocket 34 than theside sections 1152, the portions of the lugs 31 that are laterallyaligned with the central channel 1150 can be provided with studs thatare longer than the studs 1160 shown in FIGS. 44 and 45. Alternatively,the portion of the endless drive track 30 that is laterally aligned withthe central channel 1150 can be provided with lugs 1131 (shown in dottedlines in FIG. 45) that are longer than the lugs 31.

Turning now to FIG. 46, a heat exchanger assembly 1200 will bedescribed. The heat exchanger assembly 1200 is the same as the heatexchanger assembly 1100 described above, except that the surface of theside and bottom sections 1152, 1154 of the portion 1128 is provided withdimples 1202 and the surface of the central channel 1150 of the portion1128 is provided with fins 1204. The dimples 1202 and the fins 1204increase the heat exchanging surface area of the portions of thepassages to which they are connected, thereby improving the heatexchanging efficiency of the portion 1128. It is contemplated that thedimples 1202 or the fins 1204 could be omitted. It is also contemplatethat dimples and/or fins could be provided on other portions of the heatexchanger assembly 1200. It is contemplated that features other thandimples and fins that increase the heat exchanging surface area of theheat exchanger assembly 1200 could be provided instead of or in additionto the dimples 1202 and fins 1204. It is contemplated that portions ofthe heat exchanger assemblies previously described above with respect toFIGS. 4 to 37 could also be provided with dimples, fins and/or otherfeatures increasing the heat exchanging surface area.

Modifications and improvements to the above-described implementations ofthe present technology may become apparent to those skilled in the art.The foregoing description is intended to be exemplary rather thanlimiting. The scope of the present technology is therefore intended tobe limited solely by the scope of the appended claims.

What is claimed is:
 1. A heat exchanger assembly comprising: a top part; and a bottom part disposed below the top part and being joined to the top part, at least one of the top and bottom parts defining a recess, the top and bottom parts defining therebetween a passage formed in part by the recess, the passage having: a first portion of the passage extending along a first side of the heat exchanger assembly; a second portion of the passage extending along a second side of the heat exchanger assembly; an inlet fluidly communicating with the first portion of the passage near a first end of the passage; and an outlet fluidly communicating with the second portion of the passage near a second end of the passage, wherein the passage is adapted such that fluid enters the passage via the inlet, then flows in the first portion of the passage in a first direction, then flows in the second portion of the passage in a second direction opposite the first direction, and then exits the passage via the outlet.
 2. The heat exchanger assembly of claim 1, further comprising: a front portion; a middle portion rearward of the front portion; and a rear portion rearward of the middle portion, at least one of the front and rear portions being curved from the middle portion, the at least one of the front and rear portions extending below the middle portion.
 3. The heat exchanger assembly of claim 1, wherein fluid flowing in the passage from the inlet to the outlet flows along at least a majority of the passage.
 4. The heat exchanger assembly of claim 2, wherein the front portion is curved from the middle portion.
 5. The heat exchanger assembly of claim 4, wherein the rear portion is curved from the middle portion.
 6. The heat exchanger assembly of claim 1, wherein the bottom part defines the recess.
 7. The heat exchanger assembly of claim 6, wherein the top part defines at least one other recess, the passage being also formed in part by the at least one other recess.
 8. The heat exchanger assembly of claim 2, wherein the passage extends longitudinally along a first lateral side of the heat exchanger, then laterally along the rear portion, then longitudinally along a second lateral side of the heat exchanger and then laterally along the front portion.
 9. The heat exchanger assembly of claim 2, wherein the passage extends at least in part along the middle portion and the at least one of the front and rear portions.
 10. The heat exchanger assembly of claim 2, wherein at least a portion of the passage defined in the middle portion is wider than at least another portion of the passage defined in the middle portion.
 11. The heat exchanger assembly of claim 1, wherein at least a portion of the passage is thicker than at least another portion of the passage.
 12. The heat exchanger assembly of claim 2, wherein the recess is a first recess and the passage is a first passage; the heat exchanger assembly further comprising another part defining a second recess, the other part being joined to one of the top and bottom parts, the other part and the one of the top and bottom parts to which the other part is joined defining therebetween a second passage formed in part by the second recess, the second passage having another inlet and another outlet, the second passage being fluidly separate from the first passage.
 13. The heat exchanger assembly of claim 12, wherein the other part is curved; and wherein the other part is joined to the middle portion and the at least one of the front and rear portions being curved from the middle portion.
 14. The heat exchanger assembly of claim 13, wherein the first passage extends at least in part longitudinally along one side of the second passage.
 15. The heat exchanger assembly of claim 2, wherein the passage extends at least in part along the front portion; wherein a width of a portion of the passage extending along the front portion is at least three quarters of a width of the front portion.
 16. The heat exchanger assembly of claim 1, wherein the inlet of the passage is rearward of the outlet of the passage; and wherein from the outlet, the passage extends forwardly then laterally.
 17. The heat exchanger assembly of claim 4, wherein the recess extends at least in part along the middle portion and the front portion and is curved to follow a curvature defined by the front portion and the middle portion.
 18. The heat exchanger assembly of claim 2, wherein at least one of the inlet and outlet is defined in the at least one of the front and rear portions extending below the middle portion.
 19. The heat exchanger assembly of claim 18, wherein: the at least one of the front and rear portions extending below the middle portion is the front portion; and the outlet is defined in the front portion.
 20. The heat exchanger assembly of claim 1, wherein the inlet and outlet are adapted for fluidly communicating with a motor. 